Update dependencies and .npmignore

[ayaka14732]

1. The dependencies are too old. When I run npm install, I got 6 vulnerabilities (3 low, 1 high, 2 critical).
2. eslint should be installed as devDependencies rather than dependencies.
3. Commit package-lock.json.
4. Update node versions from 5-7 to 11-15 to fix CI build error (see https://github.com/adiwajshing/Baileys/issues/376).
5. Update .npmignore. Add /.eslintrc to the ignore list.

[ayaka14732]

Any update on this?